@article{TRSPY_1984_166_a14,
     author = {S. P. Novikov},
     title = {Critical points and level surfaces of multivalued functions},
     journal = {Informatics and Automation},
     pages = {201--209},
     publisher = {mathdoc},
     volume = {166},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1984_166_a14/}
}